The evaluation of the remodeling of soft biomaterial implants often involves surgical removal of the implant for subsequent histological assessment. This approach is very resource intensive, often destructive, and imposes practical limitations on how effectively these materials can be evaluated. Magnetic resonance imaging (MRI) has the potential to non-invasively monitor the remodeling of collagen sponges, specifically the biodegradation, cellular infiltration, extracellular matrix deposition and angiogenesis within the sponge. This project involves the development of an in vivo model system for the evaluation of collagen-sponge remodeling using MRI and conventional histological techniques. Collagen sponges made using insoluble bovine collagen, and subjected various crosslinking treatments, were implanted subcutaneously into rats. Changes in water T2 relaxations times, water apparent diffusion coefficients (ADC), and MRI contrast agent uptake/washout were collected using spin-echo and diffusion-weighted MRI pulse sequences. These measurements were compared with histological assessments of sponge remodeling. Regions of differential cellularity were distinguished using calculated T2 maps and confirmed by histology. Calculated ADC maps corroborated these results and showed a decreasing trend with increased tissue in-growth. Results from MRI-contrast-agent studies were consistent with the development of angiogenesis within the sponge over time. The MRI approach allows for longitudinal studies that significantly reduce the resources required to evaluate these materials as well as improves the quality of the statistical information obtained from these studies.
Worcester Polytechnic Institute
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Kandasamy, Sivakumar P., "In vivo monitoring of collagen-sponge remodeling using MRI" (2007). Masters Theses (All Theses, All Years). 180.
collage remodelling, in vivo, MRI, Implants, Artificial, Biomedical materials, Magnetic resonance imaging